| AVS 54th International Symposium | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterials Interfaces Poster Session |
| Presenter: | X. Liu, University of Wisconsin-Madison |
| Authors: | X. Liu, University of Wisconsin-Madison F. Zheng, University of Wisconsin-Madison A. Jürgensen, Canadian Synchrotron Radiation Facility, Synchrotron Radiation Center V. Perez-Dieste, Universitat Autònoma de Barcelona, Spain D.Y. Petrovykh, University of Maryland and Naval Research Laboratory N.L. Abbott, University of Wisconsin-Madison F.J. Himpsel, University of Wisconsin-Madison |
| Correspondent: | Click to Email |
Surface science has made great strides towards tailoring surface properties via self-assembly organic molecules. It is now possible to functionalize surfaces with complex biomolecules, such as DNA and proteins. However, probes of the chemical orbitals involved in this process have remained scarce. Here we show how NEXAFS (Near Edge X-ray Absorption Fine Structure spectroscopy) can be used to characterize the assembly of biological molecules at surfaces in atom- and orbital-specific fashion. The technique is illustrated by self-assembled monolayers with customized terminal groups. Applications are demonstrated by DNA oligonucleotides and Ribonuclease A1, a small protein containing 124 amino acids. The N 1s absorption edge is particularly useful for characterizing DNA and proteins, because it selectively interrogates the π* orbitals in nucleobases and the peptide bonds in proteins. Information about the orientation of molecular orbitals is obtained from the polarization dependence. Quantitative NEXAFS models are developed to explain the polarization dependence in terms of molecular orientation and structure.
1Xiaosong Liu et al., Langmuir 22, 7719 (2006).